[Effects of Suaeda glauca planting and straw mulching on soil salinity dynamics and desalination in extremely heavy saline soil of coastal areas]

Ying Yong Sheng Tai Xue Bao. 2018 May;29(5):1686-1694. doi: 10.13287/j.1001-9332.201805.034.
[Article in Chinese]

Abstract

To elucidate the seasonal variations in soil salinity and its driving factors, and to explore the effects of planting Suaeda glauca and straw mulching on soil desalination and salinity controlling, a field experiment was conducted in extremely heavy saline soil of coastal areas in Rudong, Jiangsu Province. There were four treatments: control (bare land, CK), planting S. glauca (PS), straw mulching A (at 15 t·hm-2, SM-A), straw mulching 2A (at 30 t·hm-2, SM-2A). Climate factors (including rainfall, atmospheric temperature, sunshine duration, and atmospheric evaporation) and soil salinity dynamic changes were determined from May 2014 to May 2015. Results showed that: (1) The seasonal variation of soil salinity was obvious in the bare ground (CK), with the lowest (8.69 g·kg-1) during June-August and the highest (26.66 g·kg-1) during September-December. The changes of soil salinity in topsoil (0-20 cm) were more intense than that in sub-topsoil (20-40 cm), with the changes in sub-topsoil having somewhat time lag compared the topsoil. (2) Soil salinity in CK treatment had a significantly linear correlation with the cumulative rainfall and evaporation-precipitation ratio of the fifteen-day before sampling. The results from multifactor and interphase analysis indicated that the increases of rainfall would promote soil desalinization. The rise of atmospheric temperature could exacerbate soil salt accumulation in surface soil. The interaction between rainfall and atmospheric temperature would have a positive effect on soil salt accumulation. (3) PS treatment did not alter the seasonal variation in soil salinity, but it reduced soil salinity in topsoil. (4) In SM-A and SM-2A treatments, the relationship of soil desalinization rate (%, Y) and treatment time (days, X) was expressed as Logistic curve equation. Moreover, the soil desalination rate was over 95.0% in the topsoil after 90-100 days of straw mul-ching treatment and was over 92.0% in sub-topsoil after 120 days of straw mulching treatment. The soil salinity in SM-A and SM-2A treatments fluctuated below 0.60 g·kg-1 and 1.00 g·kg-1, respectively in topsoil and sub-topsoil. Considering the desalination and economic costs, a suitable amount of straw mulching (such as 15 t·hm-2) before rainy season was recommended, which would promote the soil desalinization and reclamation in extremely heavy saline soil of coastal areas.

为探明沿海滩涂极重度盐土盐分动态规律及其影响因子,并探讨盐生植被和秸秆覆盖下土壤的脱盐及控盐效果,2014年5月—2015年5月,在江苏沿海滩涂极重度盐土中进行田间试验,设置4种处理:对照(裸地,CK)、种植碱蓬(PS)、15 t·hm-2秸秆覆盖(SM-A)和30 t·hm-2秸秆覆盖(SM-2A),监测气候因子和土壤盐分的动态变化.结果表明: (1)滩涂裸地表层土壤盐分具有显著的季节性变化特征,表现为在6—8月盐分降低至最低值(8.69 g·kg-1),9—12月呈现积盐作用,最大值为26.66 g·kg-1;表层土壤盐分变化比亚表层更剧烈,而且亚表层盐分变化相对于表层具有一定的滞后性;(2)相关分析表明,滩涂裸地表层盐分变化与采样前15 d的累积降雨量及蒸降比具有显著的线性关系;多因子及互作逐步分析表明,降雨量增加可以显著促进脱盐作用,大气温度升高可加剧盐分积累,降雨量和大气温度的互作效应增加会对盐分累积产生正效应;(3)PS处理没有显著改变土壤盐分的季节性变化规律,但降低了表层土壤盐分;(4)SM-A和SM-2A条件下,土壤脱盐率与覆盖处理天数回归拟合符合Logistic曲线,且经过雨季覆盖处理90~100 d后表层土壤脱盐率均可达到95.0%以上,覆盖处理120 d后亚表层土壤脱盐率均可达到92.0%以上,之后表层和亚表层土壤盐分分别在0.60和1.00 g·kg-1以下波动.综合考虑脱盐效果和经济投入,在梅雨季节前(4—5月)采用15 t·hm-2秸秆覆盖,可能是未来滩涂极重度盐土进行快速脱盐和改良的重要措施.

Keywords: climate factor; extremely saline soil; halophyte; salinity change; straw mulching.

MeSH terms

  • Agriculture
  • Chenopodiaceae*
  • Salinity*
  • Sodium Chloride
  • Soil / chemistry*

Substances

  • Soil
  • Sodium Chloride